JPS5918144B2 - Mold manufacturing method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a split mold used for blow molding,
By adding structural improvements to the mold prototype, it is possible to encapsulate it in the outer frame with high precision, and the left and right split molds can be created at the same time, and the mating surfaces of the resulting split molds match extremely precisely. This invention relates to a mold manufacturing method.

Conventionally, the prototype mold for blow molding is made of materials such as wood and plaster 15, and as shown in Fig.
, 2 are brought together at the boundary surface with a dowel pin 3 without any gap.

In order to create a mold from this mold prototype, a mold must be made using methods such as metal spraying or resin injection.
As shown in FIG. 2, when forming the molding layer 4,
Because it is necessary to fix the model, the process is performed with the model broken.
That is, in the conventional method, left and right split molds are manufactured separately. Such a method not only takes time and effort to manufacture, but also often leaves the left and right 25 pieces not perfectly aligned when the mold is completed. As a result, when a blow molded product was created using a mold manufactured by the conventional method, burrs were sometimes generated on the parting line (mating surface) of the created blow molded product.
Although the explanation has been delayed, FIG. 3 shows a completed state 30 of one of the split molds, with the molding layer 4 forming a recess, the outer frame 5, and the stone mold. Backing material 6 made of resin or low melting point metal, etc.
It is formed by Note that the molding layer 4 and the backing material 6 may be revealed later or may be made of the same material at the same time, in which case it is virtually impossible to distinguish between them. The present invention is a manufacturing method that eliminates the drawbacks of the conventional methods as described above, and has the advantage that by creating the left and right sides of the split mold at the same time, both molds can be matched with high accuracy.

That is, specifically, a mold model having a structure in which two or more protruding rods pass through the left and right split mold prototypes separated by a mating plate, and the protruding rods are attached to the outer frame. fixed,
In addition, the mold prototype is enclosed in the outer frame in a state where the laminated plate also serves as a partition of the outer frame, and a filler is injected into the void created by the mold and the outer frame and solidified. . In another example of the present invention, a molding layer is formed on the surface of the above-mentioned mold master by means such as metal spraying or electroforming, and then the mold is charged into the outer frame. There is. The manufacturing method of the present invention will be further explained in detail below with reference to FIGS. 4 to 9 of the drawings.

FIG. 4 shows the prototype of the mold according to the present invention, in which the left and right split molds 7 and 8 are divided at the center, and a mating plate 9 is interposed between them. The protruding rod 10 is passed through the original shapes 7 and 8 of the left and right split molds and the mating plate 9. Two or more protruding rods 10 are required because they are used to fix the position of the original mold when it is later inserted into the outer frame. The prototype of such a mold is made of materials such as wood, plaster, metal, and plastic. Examples made of wood are shown in Figures 10a-c. In other words, divide the square timber 11 in half,
After joining the left and right sides with the dowel pin 12, two or more through holes are drilled perpendicularly to the mating surface using a drill or the like. This through hole 13 is a hole for inserting a protruding rod, and is shown in FIG.
As shown in the figure, after cutting the divided square timbers 11 into original shapes 7 and 8 in a combined state, the dowel pins 12 are removed and the protruding rods 10 are inserted into the through holes 13 through the mating plates 9. . This completes the prototype of the mold shown in Figure 4, but other manufacturing methods are similar and have minor differences; the only difference is the selection of the material for the prototype. In the mold manufacturing method of the present invention, the procedure for forming a molding layer on the master mold in advance is as shown in FIGS. 5 to 8. That is, when making a mold using the mold pattern according to the present invention, a metal molding layer 14 is formed on the surface of the mold pattern by metal spraying or electroforming as shown in FIG. will be formed. To do this, it is common to apply a release agent such as silicone resin to the outer surface of the master mold (protruding rod, mating plate, master mold), and then coat metal on top of this to form the molding layer 14. It is. Next, the prototype is inserted and fixed into the steel outer frame 15 that has been manufactured in advance. The outer frames are a set of two on the left and right, and each has a hole 16 through which both ends of the protruding rod 10 are passed and the model is fixed in the outer frame. By fitting the protruding rod 10 into this hole 16, the prototype can be fixed in the outer frame 15. At this time, it should be noted that the laminated plate 9 also serves as a partition for the outer frame 15. In this state, as shown in FIG. 6, a filler, in this case a low melting point alloy (for example, a Zn alloy, a Bi-Sn alloy, etc.), is poured into the filling port 17 at the top of the outer frame to form a lining. After the low melting point alloy backing material 18 has solidified, the ejecting rod 1
Remove 0 from one side. As shown in FIG. 7, when the split mold 19 is separated to the left and right with the mating plate as the boundary and the original mold is extracted, the protruding bar marks 20 and the filling opening 17 of the backing material remain as voids. This part is replenished with a low melting point metal to fill the void. At this time, marks remain on the surface of the mold 19, but it is finished by polishing. After this, the base 21. Once the cutout portion 22 is attached, a split mold for blow molding is completed as shown in FIG. Another manufacturing method using the mold prototype of the present invention will be described next.

This method is shown in FIGS. 9a to 9c, in which the formation of the molding layer 14 as in the method described above is omitted, and molding and lining are performed simultaneously with the mold prototype enclosed in the outer frame. The mold prototype 23 shown in FIG. 4 is fixedly inserted into the outer frame 15 with a release agent applied to its surface, and then a filler 24 such as a low melting point alloy or cast iron is attached to the outer frame 15. It is sufficient to inject it into the space created between the mold 23 and solidify it. After solidification is complete, the process of pulling out the ejector rod and removing the prototype from the mold, pouring the same material into the ejector rod trace 20 and the filling port 1r, and polishing and repairing unnecessary parts remains the same as before. . Base 2
The same goes for attaching 1 and the cut-out portion 22 to the mold and completing the process. As described above, according to the method for manufacturing a mold of the present invention, the original shape of the mold can be made by inserting the plunger into the through hole drilled in the material for the original mold before the original mold is created. Even if a partition plate is used, the mating surfaces will match without dimensional deviation, and since the two left and right split molds for blow molding will be manufactured at the same time, the left and right sides of the manufactured split molds will be No misalignment occurs on the mating surfaces (parting lines).

Therefore, when blow molding is performed using the manufactured mold, a molded product with no deviation of the parting line and no burrs can be obtained. As with conventional methods, the durability of the mold is 100 to 200 shots for metal spray molds and resin molds, and 5,000 to 10,000 shots for precision casting molds and electroforming molds. As with conventional methods, the molding cycle can be shortened by installing a collar pipe before pouring the backing material. The materials used for the wooden molds include cypress, magnolia, cherry blossom, lauan, cypress, oak, and pine, which have a low resin tar content, and the materials used for the metal molds include steel, brass, and aluminum. A practical example is shown below. Example 1 Oak is used as the material for a wooden pattern, cut in half with a bandsaw, and the mating surfaces are smoothed with a planer.

Next, use a drill press to make a hole in which to embed the dowel pin. Insert a dowel pin made of the same material into this hole and align the left and right block materials. Next, use a hand drill to drill two or more holes perpendicular to the mating surfaces, and use a wood lathe, chisel, etc. to create a shape close to the original shape. Then finish with sandpaper. Copper protruding rods are fitted into the two or more through-holes to complete the mold prototype using this method.

Next, the dowel pins are removed from this prototype, and a mating plate with a circular hole in the center is sandwiched between the left and right split molds.
Sn), compressed air pressure 4Kf/C7lt, injection amount 60g/
Spray with 1ii1t to a thickness of 5 mm. The metallized prototype is fitted into an outer frame with holes drilled in advance to accommodate the ejector rods. In this state, a molten backing material made of the same material as the sprayed metal is poured in, and after slowly cooling,
Remove the wooden mold and protruding rod. The same backing material is poured into the remaining traces of the protruding rod and the filling port, and after solidification, polishing is performed to remove traces from the surrounding areas. Next, the cut-out part and the cap part are fitted, and the mold is completed. By using this method, the accuracy of the bartending line has become O (previously it was 0.1m0), but we were able to suppress the occurrence of deformation and burrs in this part during molding.Also, it is possible to make left and right split molds at the same time. As a result, we were able to reduce mold production time to half of the conventional time.Furthermore, when blow molding was performed under the conditions shown in Table 1, we were able to obtain a molded product with good appearance and no parting lines. Example 2 In the same manner as in Example 1, a wooden prototype (oak) of a 50CCJIS standard bottle was made, a plying board was set in the center of the split mold, the surface of the prototype was thinly coated with silicone resin, and a release layer was applied. After forming, fit it into the outer frame and apply epoxy resin (resin:
Inject iron powder (10:1) and solidify.

At this time, if there are air bubbles, the strength will be reduced, so
After vacuum defoaming, gently inject. After it has completely hardened,
The protruding rod and wooden mold are removed, and the same material is poured into the spots such as the light filling hole, and after it hardens, it is polished. Next, the cut-out part and the cap part are fitted to complete the resin mold. By using this prototype, there will be no deviation of the parting line or burrs in one molded product, and the manufacturing time of the resin mold will be significantly shortened.The molding conditions are as follows: The number of molded pieces is 10 pieces/hour. Same as Table 1. Example 3 Two copper blocks (250 x 150 x 5 blades) were used as the material, and after smoothing the surface with a lathe, a hole was drilled on one side of both blocks to fit a dowel pin.

After incorporating pins made of the same material, use a milling machine to drill two or more through holes into which the protruding rods will be inserted. After that, using the same milling machine, cut it into a shape close to the model (1 ton flat bottle). Then, finish with a chisel, file, etc. A copper ejector pin is inserted into the through hole, and the mold prototype created by this method is completed. Next, this prototype is 0.05%
After performing a peeling treatment with selenite, the laminated plates were fitted, and the results are shown in Table 2. Perform copper electroforming and make molds. The thickness is 100 μm. After that, it is set in an outer frame, and a low melting point alloy (for example, Zn-Al-Cu→Kg alloy) is poured into it for lining. After solidification, the wooden mold and protruding rod are removed, and the traces of the injection hole are filled with low melting point alloy again, and after cooling, polishing is performed.
Furthermore, the cut-out part and the cap part are fitted, and the mold is completed. As in Examples 1 and 2, the accuracy of the mating surfaces of the split molds is O.
A molded product with a good parting line was obtained. The molding conditions are shown in Table 3. If the mold surface lacks strength, apply hard chrome plating. Moment of hope 5
Ribbon Example 4 Using plaster that had been inverted from a wooden mold as the original material, a laminated board was placed in the center of the split mold in the same way as in the previous example, and a protruding rod was set and installed in the outer frame.

Bi-Sn alloy (Bl4O%, Sn6
0%) is heated to 140°C and poured in a molten state to solidify.

The process of finishing the mold as a mold was the same as in the above-mentioned Examples, and when molding was performed under the same conditions as shown in Table 3, a mold with good shape, especially at the parting line, without molding unevenness was obtained.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams showing a conventional example of the manufacturing method of a split mold for blow molding, FIG. 4 is a front view showing a prototype of the mold used in the present invention, and FIG. 8 to 8 are explanatory cross-sectional views showing an example of the method for manufacturing a mold according to the present invention in the order of steps, FIGS. 9 a to 9 c are explanatory cross-sectional views showing other examples of the present invention, and FIG. Figures a to c are explanatory diagrams showing the steps of creating a prototype of a mold used in the present invention. 7, 8... Original form, 9... Laminated board, 10
...Protruding rod, 11... Square timber, 12.
...Dowel pin, 13...Through hole, 14.
...Mold layer, 15... Outer frame, 16...
... Hole, 17... Filling port, 18...
Backing material, 19... Mold, 20... Protruding rod trace, 21... Mouthpiece, 22... Cutout portion, 23...・Prototype, 24...Filling.

Claims (1)

[Scope of Claims] 1. Two or more through-holes for ejecting rods are formed in the half-divided left and right parts of the material for the master mold, and then cutting is performed to create the master shape of the left and right split molds. After that, the left and right split molds are separated by a mating plate, and two or more protruding rods are passed through the through holes using the mold prototype, and both ends of the protruding rods are Fixed to the outer frame, and with the mating plate also serving as a partition of the outer plate, the prototype of the mold is enclosed in the outer frame, and in the void created by the prototype and the outer frame,
A method for manufacturing a split mold for blow molding, characterized by injecting a filler and solidifying it. 2 With the left and right sides of the half-divided master mold material combined, two or more through-holes for the protruding rods are drilled, and then cut to create the master shape of the left and right split molds, and then the left and right Using a mold pattern with a structure in which the original shape of the split mold is partitioned by a laminated plate and two or more protruding rods are passed through the through holes, a molding layer is formed on the surface of the mold pattern. After that, both ends of the protruding rod are fixed to the outer frame, and with the mating plate also serving as a partition of the outer frame, the mold prototype is enclosed in the outer frame, and the mold is formed by the prototype and the outer frame. A method for manufacturing a split mold for blow molding, characterized by injecting a filler into a cavity and solidifying it.